Production wellhead assembly



May 9,1967 OTTEMAN 3,318,377

PRODUCTION WELLHEAD ASSEMBLY Filed A ril 19 p 30 64 2 Sheets-Sheet 1INVENTORI F G L. G. OTTEMAN BY: H714 IS AGENT May 9, 1967 1.. G. OTTEMANPRODUCTION WELLHEAD ASSEMBLY 2 Sheets-Sheet 2 Filed April :50, 1964 ..'A'm mm-- QZQWM a a a E Q INVENTORZ v L. G. OTTEMAN 8Y1 HM HIS AGENTUnited States Patent 3,318,377 PRODUCTION WELLHEAI) ASSEMBLY Lloyd G.Otteman, Metairie, La., assignor to Shell Oil Company, New York, N.Y., acorporation of Delaware Filed Apr. 30, 1964, Ser. No. 363,753 11 Claims.(Cl. 166-.6)

The present apparatus relates to oil well equipment for use atunderwater locations and pertains more particularly to a wellheadclosure apparatus for closing the top of a production wellhead assemblyin a fluid-tight manner while providing means for re-establishinghydraulic control of components of underwater wellhead assemblies atoffshore locations.

The wellhead apparatus of the present invention is related to andadapted to be used on wellhead assemblies of the type found in copendingapplication, Ser. No. 218,- 482, filed Aug. 16, 1962, which is acontinuation application of Ser. No. 830,587, filed July 30, 1959, andnow abandoned. A recent development in the field of oil well drilling isthe completion of wells at offshore locations with the wellhead assemblypositioned on or close to the ocean floor out of the way of ships whichmay damage it in the event of a collision. Equipment on the ocean floor,however, faces problems such as the corrosive nature of the sea waterand the presence of marine life which tends to grow and become encrustedon metallic structures below the surface of the water.

Since it is necessary from time to time to go back into a well whereverit has been completed, it is desirable to have an underwater wellheadstructure in suitable condition so that pieces of equipment can readilybe lowered from the surface of the water and attached to the wellheadstructure. It is therefore a primary object of the present invention toprovide a wellhead closure apparatus by which an underwater wellheadassembly may be entered for the purpose of carrying out workoveroperations in the well.

A further object of the present invention is to provide suitableconnecting means by which equipment can be lowered from the surface ofthe water into engagement with an underwater wellhead assembly, whichsurfaces have been protected against exposure to the sea Water and tomarine life.

Another object of the present invention is to provide an apparatus fornormally closing the top of a wellhead assembly While providing meansfor direct vertical access into the well to carry on workover operationstherein.

A still further object of this invention is to provide a Well closureapparatus including valves and fluid manifold means whereby tubingstrings may be connected to the wellhead assembly to actuate any of thevarious components of the wellhead assembly.

These and other objects of the present invention will be understood fromthe following description taken with regard to the drawing, wherein:

FIGURE 1 is a schematic view illustrating several of the componentswhich may be arranged as an underwater wellhead assembly;

FIGURE 2 is a longitudinal view taken partially in cross-section of thetop of the wellhead assembly of the present invention;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2;and

FIGURE 4 is a fragmental longitudinal view taken in cross-section of thewellhead assembly of FIGURE 2 illustrating one form of a valvestructure.

Referring to FIGURE 1 of the drawing a wellhead assembly or productioncontrol unit for an offshore well completed underwater is shown ascomprising a casinghead closure apparatus 11 for closing the top of awell casing 12 and securing the wellhead assembly thereto, the

3,318,377 Patented May 9, 1967 "ice wellhead assembly comprising a groupof power-actuated components including flow line control valves 13, 14,15 and 16, and swabbing valves 17 and 18 inthe flow lines extendingthrough the assembly, an electro-hydraulic package unit 21 containing amotor, reservoir and pump, and a second package unit 22 containing thevarious controlling pilot valves which are preferably solenoid-actuated.The entire wellhead assembly may be encased in a container 23. Thewellhead assembly may be provided with a pair of hydraulic pressurelines 24 and 25 which extend through the wall of the container 23 tooperate a well component such, for example, as a flow line con nectorshown and described in US. Patent No. 3,090,437. The casing closure unit11 and the wellhead assembly hold-down unit are provided with one ormore tubing strings 19 and 20 as described in greater detail in US.Patent No. 3,064,735. The present invention is concerned with a closureand re-entry apparatus 26 for closing the top of an underwater wellheadassembly and permitting re-entry thereto in order to service or performother operations on the well.

A Wellhead'closure and re-entry appparatus 26, in accordance with thepresent invention, is shown in FIG- URE 2 as comprising an elongatedcylindrical housing or body member 30 forming the top of the wellheadassembly.

One or more vertical conduits, such, for example, as conduits 31 and 32of FIGURE 3, extend through the entire length of the closure means andre-entry body member 30 and are in fluid communication with the tubingstrings 19 and 20 (FIGURE 1) which depend within the well casing 12. Asecond pair of vertical conduits 33 and 34 extended downwardly into orthrough the body member 30 to provide fluid communication with varioushydraulic components of the wellhead assembly. These conduits 33 and 34are each preferably provided with one or more seating shoulders orannular recesses such as those illustrated at 35-39 whereby varioustools, valves and/ or other devices may be definitely positioned atvarious points therein.

Extending through the side wall of the body member 30 near the bottom ofconduits 33 and 34 are side conduits 40 and 41 arranged in fluidcommunication with each other, as by a flushing fluid by-pass line 42which may bend around the outside of the body member 30 as illustratedin FIGURE 3 or may form an integral part of said body member.

Each of the vertical conduits 33 and 34 and the body member 30 are alsoin communication through the wall thereof with one or more conduits 43,44 and 45 (FIG- URE 2) which lead to and are in communication withvarious hydraulically-operated components of the wellhead assembly.Thus, for example, the vertical bore 33 is in communication throughconduit 46 and thence through a fluid port 47 in the stem 48 of valve49, and into conduit 51 to which conduit 44 is connected. As shown inFIGURE 4, the actuator head 53 of an actuator tool positioned in bore 33engages the end 54 of the valve stem 48 which normally protrudes intothe vertical conduit 33 and forces the stem 48 back against thecompression spring 55 so as to open the valve 49 and bring the fluidconduit 51 into communication with the conduit 46. The actuator head 53is provided with upper and lower tapered surfaces 56 and 57,respectively, so that the actuator head 53 can open or pass a valvewithout hanging up on it.

As shown in FIGURE 2, the re-entry body member 30 is also provided withany number of other valves 58 through 62 which are similar to valve 49.Since the flow conduits 62 and 63 come away from the valves 58 and 59,respectively, at an angle to the flow conduit 51, as

3, shown in FIGURE 3; for ease of illustration they are not included inFIGURE 2. However, the conduits 51, 62, and 63 are in communication atone end with the flow conduits 44, 45 and 43, respectively, and on theother end with the conduit 46 which is in communication with thevertical conduit 33. Preferably, the inlet end of the conduit 46 may beprovided with any suitable type of a screen, such for example, as ,acylindrical screen 65a which is seated on a shoulder 37a formed on thewall of the vertical conduit 33, while the upper end of the screen 65may be locked in place, as by screw threads 66. Ina like mannerverticalconduit 34 is provided with a cylindrical screen 65; However, insome instances, when vertical conduit 34 is being used as a return linefor fluids passing upwardly through conduit 34, it may be preferable toomit the screen 65 from the conduit 34 thereby preventing any particlesin the system from clogging the outside of the screen and preventing thereturn of fluid through the screen. Normally, however, two screens 65and 65:1 are employed especially during the flushing period when fluidis flushed down conduit 33 around the flushing fluid bypass line 42 andup the vertical conduit 34.

The top of the body member 30 may be recessed, as at 70. The recess 70is provided to receive a suitable plug (not shown) having at least aportion of the outer surface made of rubber whereby a fluidtight seal isformed between the plug and the inner wall of the body member I 30within the recess 70 so that the top of one or more .vertical conduits,for example, 33 and 34, passing down through the body member, are closedin a fluidtight manner. Preferably, the wall of the recess 70 isprovided with an annular groove 71 for receiving spring-loaded latchingvdogs or fingers adapted to seat within the recess.

The construction of a preferred plug 69 for sealing the upper end of abody member of the present invention 'is described in detail in US.Patent 3,050,127. It is to be understood that rather. than forming therecess 70 in the top of the'body member 32 to receive a plug, a cap-typeis provided withan annular recess 74 cut in the outer surfacevthereof,io r any other suitable anchoring device formed onthe outersurface thereof, at least the upper portion of thebody member 30 ispreferably encased-in a temporarily removable or retractable sleevewhich may act as an outer casing to minimize corrosion and the growthofmarine organisms on the outer surface of the body member 30 whichmightprevent the orientation of the running tool head or other equipment.Such a protective outer casing on the body member 30 may take the form,as illustrated in FIGURE 2, of a spring-loaded bellows sleeve in theform of a thin flexible wall 75 which may befixedly secured at the topand bottom to ring members 76 and 77, respectively, the upper, ringmember 76 being slidably mounted in a low-pressure fluidtight engagementwith the outer surface of the body member .30. 'A compression springarranged within the flexible s1eeve'75 and between ring members 76 and77 maintains the-sleeve 75 in its normally extended position, asillustrated. The ring members 76 and 77 may be covered with rubber orany other suitable sealing means to form a substantially low-pressurefluidtight seal around the body member and against a plug 69 (FIGURE '1)when it is positioned in recess 70.2 A seal of thistypeis illustrated inFIGURE 2 as element 79. The spring-loaded protective bellows or sleeve75' extends from the top of the body member 30 downwardly adistancesulficient so that in its operative position the sleeve covers atleast'allof the outer surface of the body member from the top thereof toa point below the annular groove 74 to be engaged by a running tool, andalso extends a suflicient distance below this point so that thespring-loaded sleeve may be compressed Without being injured. Aspringloaded chemically inert bellows is preferred. The wall 75 of thesleeve can be made of flexible metal or any flexible rubber-like orplastic material. A port in the ring member 77 is provided with a greasefitting 81 by which a grease may 'be injected into the annular spacebetween the outer surface of the .body member 30 and the inner surfaceof the sleeve 75. This displaces any sea water which has entered.

While the upper ends of the vertical conduits 33 and 34 are illustratedas being of the same diameter, it is to be understood that they may beof different diameters to facilitate the running of tubing string intothe various conduits 33 and 34 and maintain identity as to which one isconnected to which tubing, to be inserted later. Thus, if verticalconduit 33 had a diameter an eighth of an inch larger than conduit 34,the larger of two tubing strings would be run into the wellhead assemblyfirst to make sure that it was seated in conduit 33. Only a singletubing string 82 is illustrated as having its lower end positionedwithin the upper end of conduit 33, it being understood that a secondtubing string could be similarly inserted in the upper end of conduit34.

Any suitable type of latching means may be employed to secure the lowerend of a tubing string 82 in the upper end'of its mating conduit 33. Forexample, simple screw threads may be employed or a combination of a pinand J-slot mechanism, both being well knownto the art. Alternatively,the recessed upper end of the vertical conduits 33 and 34 may beprovided with a series of screwthread shoulders in which the lower endof a tubing string may be stabbed. In this case, the lower end of thetubing string 82 is provided with a helically-wound spring 83 which. isadapted to stab into seating position by vertical movement of the tubingstring and may be later disconnected therefrom by rotation of the tubingstring to the right. Connections of this type are common to the art andare manufactured by Baker Oil Tool Company.

In order to enter a wellhead assembly closed by the apparatus inaccordance with the present invention, a string of pipe known as amarine conductor pipe (not shown) and having a running head secured'tothe lower end thereof would be lowered from a drilling barge downthrough the water to the ocean floor in a manner described in copendingapplication Ser. No. 218,482 filed Aug. 16, 1962. As the running andlatching head of the marine conductor pipe is lowered down on the top ofthe body member 30, which at this time would still be closed at the topby means of a plug 69 (FIGURE 1), the lower end of the running head orpipe string would come in contact with the upper ring 76 of theprotective sleeve unit 75-78, forcing it downwardly along the side ofthe body member 30. By. providing a skirt 84 extending.

downwardly'from the slidable ring 76, damage to the sleeve unit byextreme compression is prevented. A fishing tool would then be run downto remove the plug from the recess 70 and, after running tubular strings(not shown) into conduits 31 and 32, separate tubing strings,

as 82, would be run into the vertical conduits 33 and 34 and lockedtherein. Fluid would then be pumped down tubing string 82 from thevessel at the surface, and forced through vertical conduit 33, aroundflushing by-pass line 42, up through the vertical conduit 34 and thenceupwardly through a mating tubing string (not shown), if desired, to thesurface.

With vertical conduits 33 and 34 having been thoroughly flushed out,which action also cleans the inner surfaces of the cylindrical screens65 and 65a, a plug 85 'is dropped or run down one of the conduits, sayconduit 33 so as to close the flushing fluid bypass line 42. The

plug 85 is preferably run at the lower end of a valve-actuating toolwhich may comprise a valve actuator head 53 with a shaft 86 connectingit to the plug 85 at its lower end and with a hollow perforate stem 87connecting it to a suitable hollow or tubular latching body 88 adaptedto seat in the lower end of the tubing string 82 and being securedtherein, if desired, against upper movement by suitable latches 89. Thelatches 89 are only necessary in the event that fluid is to becirculated upwardly through one of the valves 49, 58, or 59 and thenceup through the tubular latching body of the valve actuator mechanism.The combination valve actuator mechanism together with the plug 85 maybe lowered and retrieved by wire line in a manner well known to the art.Preferably, it would be run in on a wire line and pulled back until thelatches 89 latched in their mating grooves so that the operator would becertain that the valve actuator head 53 was positioned opposite thevalve to be opened. Alternatively, other spacing arrangements may bemade to assure the operator that the proper valve is open. Thus, thestem 87 may be selected of a length such that when the valve actuatingmechanism is seated in the lower end of the tubing string 82, the propervalve would be open. Alternatively, the position of the valve actuatorhead could be adjusted by changing the length of the shaft 86 betweenthe plug 85 and the valve actuator head 53.

In the event that wellhead assembly employed hydraulically-operatedcomponents such as valves, lock down devices, etc., which were actuatedin both directions hydraulically, that is, to an open or closed positionor to a locked or unlocked position by applying hydraulic pressure inone direction or the other, it may be seen that the apparatus of thepresent invention could be employed to operate threehydraulically-operated wellhead components since the body member isprovided with six valves 49, 58, 59, 60, 61, and 62 in the controlconduits.

Thus, in order to pump hydraulic pressure fluid through valve 58 tooperate a wellhead component, the corresponding valve 60 on the otherside of the body member must be opened to allow hydraulic fluid from inback of the piston of the hydraulically-operated component to move upconduit 34. In this case, therefore, it would be necessary to insert avalve-actuating mechanism as described with regard to the one in conduit33, to be placed or dropped in the lower end of a second tubing string(not shown) which would be latched in the upper end of vertical conduit34. The actuated tool in conduit 34 would not need to have a plug 85attached to the lower end thereof as a single plug is all that isnecessary to plug the flushing fluid by-pass line 42.

If on the other hand the hydraulically-operated components of thewellhead assembly are spring-loaded in one direction, it is quiteapparent that only the single tubing 82 would be needed in order tooperate a single valve, say valve 58, in order to provide hydraulicpressure fluid to the wellhead conduit to actuate it. Thus, in thearrangement illustrated in FIGURE 2, the six valves could be employed tocontrol auxilliary hydraulic pressure fluid lines to siX components.

I claim as my invention:

1. In a well installation having pressure-fluid actuated componentslocated underwater at an offshore location, a re-entry head on said wellinstallation comprising:

a body member having a pair of longitudinally fluid passageway boresclosed at their lower ends and extending downwardly from the upper endof said body member,

flushing conduit means interconnecting the lower end of said pair oflongitudinal bores whereby fluid may be flushed down one bore and up theother bore,

side conduit means through the wall of said body member in communicationbetween at least one of said longitudinal bores and at least one of saidpressureactuated components of said well installation,

said body member having means above said side conduit means forreceiving and sealing a removable flow conductor, and

valve means in said side conduit means for controlling fluid flowtherethrough,

said bore having said side conduit means being provided below said sideconduit means with an internal annular seal surface engageable bysealing means of a well tool.

2. The apparatus of claim 1 including filter means carried in said boreacross the opening of said side conduit means.

3. The apparatus of claim 1 wherein each of said longitudinal bores isprovided with side conduit means and including valve means in all ofsaid side conduit means.

4. The apparatus of claim 1 wherein said valve means of said sideconduit means include valve stem means normally extending into the boreof said body member and engageable by a valve operating well tool whensaid well tool is positioned in said bore.

5. The apparatus of claim 4 well tool means positioned in the bore ofsaid body member at a point opposite to and engagement with said valvestem means of said valve means.

6. The apparatus of claim 5 wherein said well tool means is providedwith seal means at the lower end thereof for engaging said seal surfaceof said bore to close said flushing conduit means.

7. The apparatus of claim 1 wherein both of said bores are provided withside conduit means and valve means for closing said side conduit means.

8. The apparatus of claim 7 wherein both of said longitudinal bores areprovided with means for receiving and sealing flow conductors.

9. The apparatus of claim 8 including flow conductors having their lowerends sealed in the bores of said body member and being of a length toextend to a point above the surface of a body of water in which the wellinstallation is positioned.

10. The apparatus of claim 9 including sealing means carried on theouter surfaces of said flow conductors near the lower ends thereof forengaging the inner surfaces of said bores of said body members above theside conduit means thereof, and internal groove latch means on the innerwall of said flow conductors near the lower ends thereof, said groovelatch means being engageable by locking means of well devices forreleasably securing well devices in said conductors.

11. The apparatus of claim 10 including valve actuating well deviceshaving latching means for engaging said internal groove latch means andhaving valve stem actuating means carried at a predetermined distancebelow said latching means to engage said valve stem means of said valvemeans.

References Cited by the Examiner UNITED STATES PATENTS 3,054,456 9/1962Hammaker 16646 X 3,064,735 11/1962 Bauer et a1. 166.6 3,086,590 4/1963Jackson et al. 166.6 3,142,337 7/1964 Poorman et al. 166.6 3,163,22412/1964 Haeber et al. 166.6 3,186,486 6/1965 Rhodes et al. -7 X3,189,098 6/1965 Haeber 166.6 3,219,117 11/1965 Johnstone et al 166-.5

CHARLES E. OCONNELL, Primary Examiner.

ERNEST R. PURSER, Examiner.

R. E. FAVREAU, Assistant Examiner.

1. IN A WELL INSTALLATION HAVING PRESSURE-FLUID ACTUATED COMPONENTSLOCATED UNDERWATER AT AN OFFSHORE LOCATION, A RE-ENTRY HEAD ON SAID WELLINSTALLATION COMPRISING: A BODY MEMBER HAVING A PAIR OF LONGITUDINALLYFLUID PASSAGEWAY BORES CLOSED AT THEIR LOWER ENDS AND EXTENDINGDOWNWARDLY FROM THE UPPER END OF SAID BODY MEMBER, FLUSHING CONDUITMEANS INTERCONNECTING THE LOWER END OF SAID PAIR OF LONGITUDINAL BORESWHEREBY FLUID MAY BE FLUSHED DOWN ONE BORE AND UP THE OTHER BORE, SIDECONDUIT MEANS THROUGH THE WALL OF SAID BODY MEMBER IN COMMUNICATIONBETWEEN AT LEAST ONE OF SAID LONGITUDINAL BORES AND AT LEAST ONE OF SAIDPRESSUREACTUATED COMPONENTS OF SAID WELL INSTALLATION, SAID BODY MEMBERHAVING MEANS ABOVE SAID SIDE CONDUIT MEANS FOR RECEIVING AND SEALING AREMOVABLE FLOW CONDUCTOR, AND VALVE MEANS IN SAID SIDE CONDUIT MEANS FORCONTROLLING FLUID FLOW THERETHROUGH,